It's job-hunting season on campuses across the country, and the anemic job market is adding some extra stress to spring for many millennials.

Recent college graduates are facing less unemployment than those without college degrees, but a study by the Georgetown University Center on Education and the Workforce found they are still contending with a nearly 8 percent jobless rate. And 44 percent of recent college graduates are underemployed, meaning they hold jobs that do not require a college degree, according to a separate report by the New York Fed.

But it's not just slow job growth that is hurting millennials' job search prospects. In many ways, hiring managers and others say, they are hurting themselves.

Stories abound of millennials showing up in casual clothes for formal interviews, bringing—and using—their phones during the interview and worse.

Not only that, in a survey of 22- to 26-year-old college graduates by Adecco, a staffing and recruiting company, 8 percent reported that a parent accompanied them on at least one job interview, and 3 percent said a parent actively joined the interview.

"I've had moms call me for interviews," said Dan Black, Americas director of recruiting at EY, the global firm that includes Ernst & Young, though he added that the candidates themselves were uniformly mortified when this happened.

Millennials "have been technology enabled from the minute they were able to crawl, so to speak, so they have a different way of connecting and a different way of engaging," said Kip Wright, a senior vice president with ManpowerGroup, the staffing company. As a result, he said, "they struggle with that traditional interview."

Some of the biggest mistakes recent college graduates make involve interview preparation, or a lack thereof.

In an Adecco survey of hiring managers, 75 percent said millennials' biggest interview mistake was dressing inappropriately, and almost as many said they tended to mess up by posting inappropriate material on social media. Almost two-thirds of respondents said millennials tend to demonstrate a lack of research preparation for interviews. These hiring managers also said they were three times as likely to hire a worker over age 50 as a millennial.

Black said he is often struck by millennials' casual approach. "I've gotten emails saying 'hey, it was gr8 to meet you'" after a recruiting event, he said.

But college students needn't despair. Hiring managers and recruiting experts say millennials also bring skills to their post-college jobs earlier generations lack.

"They know technology front and back. They know how to multitask at a level we can't imagine," Wright said. "If you put them in a conference room when they are trying to solve a problem and let them use their laptops, they will be networking with their own networks and they will collectively come up with solutions that you may never have thought of."

Black is similarly enthusiastic about millennials' capabilities. And Ernst & Young LLP intends to recruit nearly 12,700 professionals in the U.S. in fiscal year 2014, with nearly 7,200 coming from college campuses.

Black contends that employers need to make some adjustments to their expectations in order to work successfully with millennials—and millennials need to do the same.

"We've made lots of changes around the different technology platforms we use," he said. When his firm is training millennials, it offers podcasts and webcasts because "this is how this generation learns."

But 20-something job candidates and employees need to respect the client focus of the business, and adjust their behavior accordingly, he added.

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"I can't wear shorts to the office, much as I'd like to. That's an accommodation that the candidate's going to have to make. That's what is accepted and required to do the job."